Control mechanism for refrigerating apparatus



' 1963 E; F. HUBACKER ETAL 3,

- CONTROL MECHANISM FOR REFRIGERATING APPARATUS Filed Feb. 3, 1961 4 Sheets-Sheet 1 D 1963 E. HUBACKER ETAL 3,113,438 CONTROL MECHANISM FOR REFRIGERATING APPARATUS Filed Feb. 3, 1961 4 Sheets-Sheet 2 D 6 E. F. HUBACKER 'ETAL 3,113,433

CONTROL MECHANISM FOR REFRIGERATING APPARATUS Filed Feb. 3, 1961 4 Sheets-Sheet s w ifu w 0. Fr n. NJ 2 .45 5 6 M/// w/////////Mz V//// //Vo /////////fl/ 986.102, 1 A E. F. HUBACKER ETAL 3,113,438

' CONTROL MECHANISM FOR REFRIGERATING APPARATUS Filed Feb. 3, 1961 4 Sheets-Sheet 4 United States Patent 3,113,438 CGNTRGL MECHANISM FUR REFREGERATING APPARATUS Earl F. Hubacher, Evansville, Ind, and Saidney G. James, Kirlrwood, and William J. Allan, Aifton, Mo, assignors to Whirlpooi Corporation, a corporation of Delaware Filed Feb. 3, 1961, er. No. 86,882 18 Claims. (El. 62-155) This invention relates to control mechanisms and in particular to control mechanisms for use with refrigeration apparatus.

In conventional refrigeration apparatus, cooling is effected by moving air firstly in thermal transfer association with a suitable evaporator and thence to the compartment or compartments to be refrigerated. Moisture in the air is deposited on the evaporator in the form of frost during this operation, which frost must be periodically removed to permit efficient operation of the system. Conventionally, the defrosting of the evaporator is effected by electric heaters or by delivery of hot refrigerant gas to the evaporator. The defrosting operation is conventionally controlled by a timing device for automatic initiation thereof. The termination of the defrosting operation is conventionally controlled by a suitable thermostat sensing the temperature of the evaporator. Further, an additional control is conventionally employed to delay the operation of the air moving means for a preselected time after the defrosting operation. The relatively complicated separate control devices provided for the indicated functions have made such control of the refrigeration apparatus relatively expensive and susceptible to failure. The present invention comprehends the provision of a unitary, simple mechanism for controlling the operation of the refrigeration apparatus, providing each of the desirable functions discussed above.

Another [feature of the invention is the provision of such a control mechanism having new and improved means for operating a plurality of control switches as a function of the evaporator temperature.

A further feature of the invention is the provision of such a control mechanism having new and improved timer means preferably operative only concurrently with.

operation of the cooling-refrigerant providing means.

Still another feature of the invention is the provision of such a control mechanism having new and improved means for terminating the defrosting operation when the evaporator reaches a preselected high temperature.

A still further feature is therprovision of such a control mechanism having new and improved means for controlling the operation of the air moving means, and for initiating operation thereof immediately upon termination of the defrosting operation when the evaporator reaches a preselected low temperature.

A yet further feature of the invention is the provision of such a control mechanism which is simple, economical and compact providing long trouble-free life.

Other features and advantages of the invention will be apparent from the following description thereof taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a vertical cross section of a control mechanism embodying the invention, with portions of the electrical terminals broken away to facilitate the illustration.

FIGURE 2 is a fragmentary transverse section taken substantially along the line 22 of FIGURE 1.

FIGURE 3 is an enlarged fragmentary section taken substantially along the line 33 of FIGURE 2.

FEGURE 4 is an enlarged fragmentary transverse section taken substantially along the line 44 of FIGURE 1.

FIGURE 5 is an enlarged fragmentary horizontal section taken substantially along the line 55 of FIGURE 4.

FIGURE 6 is an enlarged fragmentary section taken substantially along the line 6-6 of FIGURE 7.

FIGURE 7 is a front elevation of the control with a schematic electrical diagram of the control mechanism superimposed.

In the exemplary embodiment of the invention as disclosed in the drawings a control mechanism generally designated ill comprises a unitary device enclosed in a housing 11 having a front opening 12 closed by a terminal panel 13 carrying five terminals l4, l5, 1.6, 17 and lit; for electrical connection through suitable wire leads to different elements of the mechanism within the housing as discussed in detail below. The control mechanism includes within housing 11 a control rod member 19, a pair of single pole, single throw snap switches 2d and 21 operated by a first actuator 22 and a single pole, double throw snap switch 23 operated by a second actuator 24. Actuators 22 and 24 are associated, as discussed in greater detail below, with the control member -19 for operation of the switches 20, 21 and 23 as a function of the temperature of the evaporator -E of a conventional refrigeration apparatus, which temperature is sensed by a conventional bulb 25 arranged to be placed in thermal transfer association with the evaporator. The bulb 25 is connected by a suitable capillary tube 25 to a spring biased expansion device 27 carried on the housing 11 for longitudinally translating the control member 19. Mechanism It) is arranged to effect automatically a defrosting operation of the evaporator by means of the action of control member 19 in conjunction with a timing device generally designated 23 which includes a bimetallic strip 2? periodically heated by an electric heater 3t) partially enclosing the strip to pivot a connector 3'1. A pawl 32 associated with the connector progressively rotates a pair of toothed wheels 34- and 35' controlling the actuator 24 in cooperation with an actuating member 36 operated by the control member 19.

Herein, switch 20* controls the means for providing the cooling-refrigerant to the evaporator, conventionally comprising a compressor, and thus may be referred to as a compressor switch; switch 21 controls the means 125 for moving the air in the refrigeration apparatus, conventionally comprising a fan, and thus may be referred to as a fan switch; and switch 23 controls the means 124 for providing heat to the evaporator, conventionally comprising an electric defrost heater, and thus may be referred to as a defrost switch. A fourth switch 37 is further provided within housing ll for controlling the energization of the timer heater 3d associated with the bimetallic strip 29 and thus may be referred to as a timer switch.

Manual adjustment of the operation of compressor switch 21 and fan switch 21 is effected by adjustment of a pivot support 38 about pivot pins 33 on housing 1.1 operated by a handle 39 disposed externally of the housing, the pivot support being arranged to adjust the relationship of the actuator 22 with the control member '19.

More specifically, control member 19 comprises a cylindrical rod having an outer end 40 extending through an opening 41 in an upper cup-shaped enclosure member 42 defining an upper housing portion of the expansion device 27. A lower cup-shaped enclosure member 43 depends from the housing 11 to define the lower housing portion of the expansion device 27. The housing 11 is provided intermediate the enclosures 42 and 43 with an enlarged opening 44 and the enclosures are secured to the housing 11 circumjacent the opening 44 by means such as screws 45. A cup-shaped diaphragm 46 extends across the interior of enclosure 43 to define an upper chamber 47, and a lower chamber 48 with which the capillary tube 226 communicates. As best seen in FIGURE 1 the lower chamber is centrally downwardly enlarged to hold a body of liquid 49 under pressure. An end plate 563 is secured to the lower end of the control member 19 to support a retainer 51 against the downward urging action of a coil spring 52 extending coaxially of the control rod between the retainer 1 and the upper enclosure 42. The plate 50, retainer 51 and the lower end 40 of the control rod cooperatively define a surface against which the dia phragm 46 is upwardly urged upon expansion of the fluid in chamber 48. Thus, as the temperature sensed by the bulb 25 rises the diaphragm is urged upwardly to move the control rod 19 upwardly against the action of spring 52. Alternatively, as the temperature sensed by the bulb 25 decreases the spring 52 urges the control rod 19 downwardly against the decreasing force applied through the diaphragm.

Actuator 22 includes a channel portion 53 having a central opening 54 through which the control rod 19 upwardly freely extends. The control rod is provided with a collar 55 which engages a longitudinally extending raised rib 56 in the web 57 of the channel portion 53 so that when the control rod 19 is urged downwardly by the coil spring 52 the actuator 22 is pivoted in a counterclockwise direction about a pair of outwardly extending ears 58 thereof received in a trapezoidal slot 59 in each of a pair of end flanges 60 of the pivot support 38. The actuator 22 is provided at its free end with a pair of actuating members 61 and 62 engaging compressor switch 219 and fan switch 21, respectively. The switches 20 and 21 may be of conventional snap switch construction, each including a fiat spring 63 connected through a suitable linkage 64 to the movable contact of the switch, i.e., movable contact 65 of switch 20 and movable contact 66 of switch 21. Movable contact 65 of switch 20 normally engages a fixed contact 67 of the switch and movable contact 66 of switch 21 is normally spaced from a fixed contact 63 of the switch 21. Thus, when collar 55 moves downwardly to pivot the actuator 22 in a counterclockwise direction as seen in FIGURE 1, the actuating member 61 through spring 63 acts to open the switch 20 and close the switch 21 at preselected points in its downward movement. Reversely, when the control rod moves upwardly, the downward force on the actuator is released whereby the springs 63 restore the switches 20 and 21 to their normally closed and normally open respective conditions.

Actuator 24 includes tabs 69 pivotally carried on pins 70. The forward end of the actuator 24 includes an actuating member '71 which engages a spring 72 associated with defrost switch 23 for controlling the movement of a movable contact 73 between fixed contacts 74 and 75 of the switch 23. The actuator 24 further includes a tongue 76 engaged by a finger 77 of the actuating member 36 for pivoting the actuator 24 in a clockwise direction when the actuating member is pivoted in a counterclockwise direction about pins 78. Such counterclockwise pivoting of the member 36 is effected by a screw connector 79 adjustably fixed to the actuating member 36 and provided with a depending ball 80 received in an upwardly opening recess 81 in the upper end of the control rod 19. As shown in FIGURE 1, the connector 79 is secured to the actuating member to the right of the pivot pins 78 and thus upward movement of the control rod 19 causes the finger 77 to be moved in a counterclockwise direction thereby.

As shown in FIGURE 1 the timing device 28 is disposed at the rear of the housing 11 with the connector 31 in the upper rear portion. As shown in FIGURE 2, the connector 31 is disposed laterally of the upper end 82 of an actuator 83 engaging a spring 84 which acts through a linkage 85 to control a movable contact 86 normally selectively contacting a fixed contact 87 of switch 37. As shown in FIGURES 1 and 2, the lower ends of the spring 84 and switch blades 88 and 89 are secured to a support 90 carried on the housing 11 by means of a bracket 91. As shown in FIGURE 1, terminals 92 and 93 extend downwardly from the support 90,

4- being connected respectively to the movable contact 86 and fixed contact 87.

Connector 31 comprises a downwardly opening U- shaped member having oppositely extending support portions 1 4 and J5 pivotally mounted on coaxial pins 96 on the housing 11. Support portion is provided with an elongated laterally extending slot 97 through which the upper end of the bimetallic strip 29 extends to pivot the connector about the axis of pins 96 as a result of the reciprocal flexing of the bimetallic strip during seriatim cooling and heating thereof. The connector .31 further includes a pair of depending flanges 98 through which are threaded a pair of screws 99 which are locked in an adjusted position by means of suitable nuts 100 to engage the upper end 82 of the actuator 33 controlling switch 37 for movement of the actuator upon pivotal movement of the connector. The pawl 32 includes an upturned end 101 which extends through a suitable slot 102 in bar support portion 95 and a coil spring 103 is connected at one end thereto and at its opposite end to a bracket 104 secured to the side wall of the housing 11 to bias the connector 31 in a clockwise direction about pins 96 as seen in FIGURE 1 and to bias the pawl 32 in a counterclockwise direction about an etfective pivot thereof on bar support 95 in slot 102.

The distal end of the pawl 32 is bifurcated to define a first finger 105 engageable with the teeth 34a of wheel 34 and a second finger 106 engageable with the teeth 35a of wheel 35. As best seen in FIGURE 1, finger 106 is downturned relative to finger 105 whereby finger 105 is retained normally out of engagement with wheel 34 until such time as the finger 106 is received in a deep toothed portion 107 of wheel 35 permitting the spring 1113 to pivot the pawl 32 sufiiciently to bring finger 105 into engagement with the teeth 34a of wheel 34. The rotation of the wheels 31 and 35 about an axle 108 on which the wheels are freely journaled is effected by the reciprocation of the pawl 32 resulting from the oscillation of connector 31 by bimetallic strip 29. Thus, as shown in FIGURE 1, during the cooling of the bimetallic strip the pawl 32 is moved to the left thereby urging wheel 35 in a counterclockwise direction one step. The wheel is retained against rearward movement at the completion of each step by a latch 109 secured to the bracket 104. Upon heating, the bimetallic strip 2? urges the pawl 32 to the right sufficiently to engage the succeeding tooth of the wheel 35 for advancing the wheel a subsequent step during the next leftward movement of the pawl. When the finger 106 moves into the deep toothed portion 107 permitting the engagement of finger 105 with the toothed wheel 34- the next leftward movement of the pawl 32 advances both wheels 34 and 35 one step.

As indicated briefly above, actuator 24 controls the defrost switch 23. Actuator 24 is itself controlled by the wheels 34 and 35 to effect a defrost operation at preselected intervals. More specifically, the wheels 34 and 35 are provided with large diameter hubs 110 and 111 respectively. Hub 1119 is provided with an outwardly opening transverse groove 112 and hub 111 is provided with a corresponding outwardly opening transverse groove 113 which, as shown in FIGURE 4, are normally dis aligned. However, once during each complete revolution of the wheel 35, it may be seen that the groove 113 is aligned with the groove 112. Further, it may be seen that once during each revolution of the wheel 34 the groove 112 is at a lowermost position in alignment with an upturned end 114 of an extension 115 of actuator 24. At the point in the movement of wheel 35 wherein the groove 113 is aligned with the groove 112 in this lowermost disposition, the upturned end 114 of actuator 24 moves upwardly into the aligned grooves as a result of the gravitational pivoting of the actuator about the pivot 70 and the urging action of spring 72.

As discussed briefly above, portion 77 of actuating member 36 serves to pivot the actuator 24 in a clockwise direction when the control rod member 19 is in an upper disposition; thus actuating member 36 serves to move the turned end 114 from the aligned grooves 112 and 113 when the temperature sensed by bulb 25 reaches a preselected high value indicative of the completion of the defrosting operation. When the turned end 114 moves downwardly from the aligned grooves, the wheel 35 will rotate a small amount sufiicient to cause disalignment of the grooves and prevent re-entry of the end 114 into the grooves when the control rod member 19 moves downwardly. This movement of the Wheel 35 is obtained by arranging the grooves and turned end 114- to be aligned when the bimetal 29 has cooled only slightly whereby a spring force is built up therein as a result of further cooling of the bimetallic strip which efiects a normal full pivoting of connector 31 when the locked wheels 34 and 35 are released.

As discussed briefly above, handle 39 provides a manual control of the operation of mechanism by adjusting the pivot support 38. Handle 39 is connected to the pivot support 38 by a cam 117 having an outturned leg 118 secured to a shaft 119 on which the handle is fixed. The upper portion of the pivot support 38 is provided with a finger 12% extending through an opening 121 in housing 11. The distan end 122 of the finger 12d bears against the periphery of cam 117, as best seen in FIGURE 3, to control the position of the actuating member as a result of rotation of the cam. A s ring wash r 123 is interposed between the cam 117 and the shaft 119 to retain the cam in the adjusted position. Resultingly, the trapezoidal slot 59 in the pivot support 38 may be suitably adjusted to selectively raise or lower the pivot point of the cars 58 of the actuator 22 for controlled engagement thereof with the control rod collar 55.

Referring now more specifically to FIGURE 7 the electrical circuitry associated with mechanism 10 for controlling the evaporator heater 124, the circulating fan 125 and the compressor 12%? includes the terminals 14, 15, 15, 7 and 18 which are connected to the control switches 2t 21 and 23. As shown, terminal 14 is connected to fixed contact 74 of double throw switch 23 and terminal 15 is connected to the moving contact 73 thereof. Terminal 16 is connected to one end of bimetal strip heater 3d and the other end of the heater 3th is connected through switch 37 to terminal 17. The fixed contact 67 of switch is connected to terminal 17 and the moving contact 65 thereof is connected to the fixed contact 75 of switch 23 and the moving contact 66 of switch 21. The fixed contact 63 or" switch 21 is connected to terminal 18. Terminal 16 is arranged to be connected to one side of a suitable power supply line, herein lead L1, which is also connected to one side of each of the defrost heater 124-, :i an 125' and compressor 126. The other side of the power supply line, herein lead L2, is connected to terminal 15. The other side of heater 124 is connected to terminal 14, the other side of fan 125 is connected to terminal 18 and the other side of compressor 126 is connected to erminal 17 to complete the electrical connections.

Operation Mechanism 10 provides a simplified control of the refriceration apparatus permitting desirable adjustment thereof as desired. In illustrating the operation of the control mechanism, the control mechanism is shown in FIGURE 1 as arranged at a time when the temperature of the'evaporator is at a high value, such as ambient room temperature. Under this condition, the fluid 49 in chamber 43 is expanded to force the diaphragm 46, and thusly the control rod member 19 upwardly to the illustrated position. In this upper position the collar 55 is positi-oned sufficiently upwardly to allow the actuator 22 to be pivoted in a clockwise direction permitting switch 2th to snap to its normally closed condition thereby energizing the compressor 126. In this position however the actuator 22 is also arranged to permit the fan switch 21 to be in its normally open condition whereby fan 125 is prevented from operating. As the temperature of the evaporator is lowered by the operation of compressor 126, the control rod is moved downwardly by the coil spring 52 against the decreased pressure of the fluid in chamber 48 causing the collar 55 to bear against the rib 56 and pivot the actuator 22 in a counterclockwise direction. When the evaporator reaches a first preselected low temperature such as 20 F. above the compressor cut-oil temperature the movement of the actuator is sufiicient to operate switch 21 through its spring 63 to close the switch and thereby energize the fan 125 to circulate refrigerating air to the chamber to be refrigerated. Further operation of the compressor 12 6 causes continued lowering of the evaporator temperature until the cut-off temperature is reached at which time the actuator 22 is pivoted sufiiciently counterclockwise to snap compressor switch 2t) to its open condition thereby terminating further operation of the compressor at this time. The switch 20 remains open until the control rod member 19 moves upwardly to permit spring 63 to pivot actuator 22 clockwise suiilciently to close the compressor switch 21), thereby initiating another refrigeration cycle as discussed above.

The defrost switch is maintained in the position of FIGURE 1 during the normal refrigerating cycles of the apparatuus by virtue of the engagement of the turned end 114 of actuator finger with the hubs of the wheels 34 and 35, thereby applying sufficient force to spring 72 to maintain this arrangement of the switch 23. In this arrangement movable contact 73 engages fixed contact '75 to complete the circuit from lead L2 to the fan and compressor 126 through switches 23 and 21, potentiating switches 25) and 21 for control of the fan and compressor as discussed above.

As bimetallic strip heater 3:; is connected in parallel with compressor 126 between lead L1 and terminal 17 operation of the timer Z8 is limited only to that time in which the compressor 126 is operating. Thus, the frequency of the defrost cycles is directly correlated with the frequency of operation of the compressor precluding,

undesirable unnecessary defrosting as may occur in conventional defrosting controls wherein the frequency of the defrosting cycle is determined without regard to the amount of operation or" the compressor.

The energization of heater 3% through switches 37, 20 and 23 causes the bimetallic strip 29 to pivot the connector 31 in a counterclockwise direction, as seen in HQ- URE 1, until actuator 83 moves sufficiently to operate linkage 85 to snap switch 37 to its open condition. As the heater 3% is now deenergized the bimetallic strip 29 cools and moves to the left, thereby urging pawl 32 tothe left a distance comparable to the space between successive teeth on the wheels 34 and 35. This, as discussed above, causes the wheel 35 to advance one step during each such cycle of the timer 28 and the wheel 34 to advance one step during each complete revolution of the wheel 35' when the finger 156 of the pawl 32 engages the deep toothed portion 19'? of the wheel 35. Herein the timer is arranged to have a cycle period of approximately one minute. Each of the wheels 34 and 35 is provided with 22 teeth. Thus, the wheel 35 completes one revolution every 22 minutes and the wheel 34 advances one step every 22 minutes. Resultingly the wheel 34 makes a full revolution approximately every 484 minutes of compressor running time. Once during each 484 minute compressor running time period, the two grooves 112 and 133 are aligned in the lowermost position, permitting the turned end 114 of the actuator 24 to move thereinto and allow the spring 72 to snap the defrost switch 23 to the position wherein movable contact '73 en' ages fixed contact 74 and is spaced from fixed contact 75. As best seen in FiGURE 7, this arrangement of switch 23 breaks the circuit to the fan 125 and compressor 126 and establishes a circuit from terminal 15 through terminal 14 to the evaporator defrost heater 1154 thereby causing defrosting of the evaporator. The heating of the evaporator causes the fiuid 49 in chamber 48 to expand, thereby raising the control rod member 33 sufficiently to pivot actuating member 36 about pivot 78 in a counterclockwise direction sufilicently to cause portion '77 thereof to depress tongue "id of actuator 24 sufiiciently to withdraw turned end 114 thereof from the aligned grooves 112 and 113. As indicated above, bimetallic strip 29 immediately moves pawl 32 sufficiently to disalign the grooves 112 and 113 and prevent re-entry of turned portion lid thereinto upon subsequent downward movement of the control rod memher as a result of the energization of the compressor 126 now permitted by the restoration of the defrost switch 123 to the condition of FlGURE 1 wherein movable contact 73 engages fixed contact 75 and resets the circuit to the compressor.

It should be noted that at the time of re-initiation of the refrigeration cycle the fan switch 21 is in normally open condition by virtue of the elevated position of the collar 55 so that the fan 3.25 does not operate immediately with the operation of the compressor. However, immediately upon the evaporators temperature being brought back down to the temperature of approximately F. above the preselected compressor cut-off temperature, the fan 125 is operated and the refrigeration of the chamber to be cooled commences.

The adjustment of the compressor cycling temperature by control handle 39 permits the collar 55 to release the actuator 22 selectively in different positions of the control rod member 19, thus permitting the housewife to regulate the temperature of the refrigerator maintained by the refrigeration apparatus. Should it be desired to discontinue all operation of the refrigerating apparatus the handle 39 may be turned sufficiently to bring the high point 127 of the cam 11'? into engagement with finger 122 of the pivot support 35, thereby pivoting the support 38 sufficiently in a clockwise direction, as seen in FIGURE 1, to raise the channel portion 53 of the actuator 22 to a point where the actuator is pivoted at all times sufficiently to open the compressor switch 29.

Having described the invention as related to the embodiment shown in the accompanying drawings, it is the intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

We claim:

1. For use in a refrigeration apparatus having an evaporator, first means for providing cooling refrigerant to the evaporator, second means for moving air in heat transfer association with the evaporator, and third means for heating the evaporator for defrosting the same, a control mechanism comprising: a control member; and operator responsive to the temperature of the evaporator for reciprocably translating the control member to a first position when the temperature of the evaporator is at a preselected high value, to a second position when the evapo rator is at a first preselected low value, and beyond said second position to a third position when the evaporator is at a second preselected low value; a first control switch for controlling the operation of said first means; a first actuator movable by said control member to open said first switch and prevent operation of said first means when said control member moves to said third position; a second control switch for controlling the operation of said second means; a second actuator movable by said control member to close said second switch and cause operation of said second means when the control member moves away from said first position to said second position; a third control switch for concomitantly controlling the operation of said third means and selectively potentiating said first and second control switches; timer means for adjusting said third switch at preselected intervals to cause operation of said third means and make ineffectual said first and second switches; and a third actuator movable by said control member disassociating said third switch from said timer means to discontinue operation of said third means when said control member moves to said first position, and concurrently potentiating said first and second control switches for operating said first and second means.

2. For use in a refrigeration apparatus having an evaprator, a compressor for providing cooling refrigerant to the evaporator, a fan for moving air in heat transfer association with the evaporator, and a heater for defrosting the evaporator, a control mechanism comprising: a control member; an operator responsive to the temperature of the evaporator for reciprocably translating the control member to a first position when the temperature of the evaporator is at a preselected high value, to a second position when the evaporator is at a fist preselected low value, and beyond said second position to a third position when the evaporator is at a second preselected low value; a first control switch for controlling the operation of said compressor; a first actuator movable by said control member to open said first switch and prevent operation of said compressor when said control member moves to said third position; a second control switch for controlling the operation of said fan; a second actuator movable by said control member to close said second switch and cause operation of said fan when the control member moves away from said first position to said second position; a third control switch for concomitantly controlling the operation of said heater and selectively potentiating said first and second control switches; timer means for adjusting said third switch at preselected intervals to cause operation of said third means and make ineffectual said first and second switches; and a third actuator movable by said control member disassociating said third switch from said timer means to discontinue operation of said heater when said control member moves to said first position, and concurrently potentiating said first and second control switches for operating said compressor and fan.

3. For use in a refrigeration apparatus having an evaporator, first means for providing cooling refrigerant to the evaporator, second means for moving air in heat transfer association with the evaporator, and third means for heating the evaporator for defrosting the same, a control mechanism comprising: a control member; an operator responsive .to the temperature of the evaporator for reciprocably translating the control member to a first position when the temperature of the evaporator is at a preselected high value, to a second position when the evaporator is at a first preselected low value, and beyond said second position to a third position when the evaporator is at a second preselected low value; a first normally closed control switch for controlling the operation of said first means; a second normally open control switch for controlling the operation of said second means; a first actuator including a first portion movable by said control member to open said first switch and prevent operation of said first means when said control member moves to said third position and a second portion movable by said control member to close said second switch and cause operation of said second means when the control member moves away from said first position to said second position; a third double throw control switch for concomi tantly controlling the operation of said third means and selectively potentiating said first and second control switches; timer means for adjusting said third switch at preselected intervals to cause operation of said third means and make ineffectual said first and second switches; and a second actuator movable by said control member for disassociating said third switch from said timer means to discontinue operation of said third means when said control member moves to said first position, and concurrently potentiating said first and second control switches for controlling said first and second means.

4. For use in a refrigeration apparatus having an evaporator, first means for providing cooling refrigerant to the evaporator, second means for moving air in heat transfer association with the evaporator, and third means for heating the evaporator for defrosting the same, a control mechanism comprising: a control rod member; an operator responsive to the temperature of the evaporator for reciprocably axially translating the control member to a first position when the temperature of the evaporator is at a preselected high value and to a second position when the evaporator is at a preselected low value; a first control switch for controlling the operation of said first means; first actuating means movable by said control rod member controlling said first switch to prevent operation of said first means when said control member moves to said third position and cause operation of said first means when said control member moves to said first position; a second control switch for controlling the operation of said second means; second actuating means movable by said control rod member to close said second switch and cause operation of said second means only when the temperature of the evaporator is below a preselected value; a third control switch for concomitantly controlling the operation of said third means and selectively potentiating said first and second control switches; timer means for selectively adjusting said third switch at preselected intervals to cause operation of said third means and make ineffectual said first and second switches; and third actuating means by said control rod member for disassociating said third switch from said timer means to discontinue operation of said third means when said control member moves to said first position, and concurrently potentiating said firs-t and second control switches for controlling said first and second means.

5. For use in a refrigeration apparatus having an evaporator, first means for providing cooling refrigerant to the evaporator, second means for moving air in heat transfer association with the evaporator, and third means for heating the evaporator for defrosting the same, a control mechanism comprising: a first control switch for controlling the operation of said first means; first actuating means controlling said first switch; a second control switch for controlling the operation of said second means; second actuating means controlling said second switch; a third control switch for concomitantly controlling the operation of said third means and selectively potentiating said first and second control switches; timer means for adjusting said third switch at preselected intervals to cause operation of said third means and make ineffectual said first and second switches, said timer means including a pair of wheels each having a first portion provided with peripheral teeth and a second coaxial portion provided with a peripheral transverse groove, an axle carrying said wheels for rotation about a common axis with said second portion juxtaposed, whereby said grooves may be aligned end-to-end in a preselected rotation relatively of said wheels, and means for progressively independently rotating said wheels about said axis whereby said grooves are aligned at preselected times; and an actuator for controlling said third switch having a portion receivable in said grooves when aligned, said actuator operating said third control switch as a result of movement of said portion into and from said aligned grooves.

6. In -a control mechanism such as for controlling a refrigeration apparatus, a timer comprising: a pair of wheels each having an axial portion provided with a pcripheral transverse groove; an axle carrying said wheels for rotation about a common axis with said portions juxtaposed, whereby said grooves may be aligned end-to-end in a preselected rotational relationship of said wheels; means for progressively independently rotating said wheels about said axis whereby said grooves are aligned at preselected times; a control switch; and an actuator for operating said control switch and having a portion receivable in said grooves when aligned, said actuator operating said 1% switch as a result of movement of said portion selectively into and from said aligned grooves.

7. In a control mechanism such as for controlling a refrigeration apparatus including a compressor, a timer comprising: a pair of wheels each having a first portion provided with peripheral teeth and a second coaxial portion provided with a peripheral transverse groove; an axle carrying said wheels for rotation about a common axis with said second port-ion juxtaposed, whereby said grooves may be aligned end-to-end in a preselected rotational relationship of said wheels; means engaging said teeth for progressively independently rotating said wheels about said axis only during such time as the compressor is operating whereby said grooves are aligned at preselected times; a control switch; and an actuator operating said control switch and having a portion receivable in said grooves when aligned, said actuator operating said switch as a result of movement of said portion selectively into and from said aligned grooves.

8. The timer of claim 7 wherein the means for progressively rotating the wheels comprises a bimetallic strip, an electric heater in thermal transfer association with said strip, a switch in series with the heater for seriatim energizing and tie-energizing said heater, and means operatively connecting the bimetallic strip and wheels for movement of at least one of the wheels one step during each cycle of energization and de-energization of the heater.

9. The timer of claim 8 wherein the means connecting the bimetallic strip and wheels includes a bifurcated pawl having one portion engaging the teeth of one wheel at all times and a second portion normally spaced from the teeth of the second wheel, said one wheel having a deep toothed portion permitting the second portion of the pawl to engage the teeth of the second wheel once during each revolution of the first wheel.

10. The timer of claim 7 wherein the teeth engaging means includes a pawl having a length preselected to position the wheels with the grooves disaligned when the bimetallic strip is in the extreme cooled position thereof.

11. In a control such as for controlling a refrigeration apparatus, mechanism comprising: a control member; a first switch; a second switch; means for translating the control member selectively to first and second positions as a function of a temperature of the refrigeration apparatus; a first movable actuator for controlling the first switch; means on the control member selectively engaging the first actuator to move the same to operate said first switch as the result of the movement of the control member toward said second position; means controlling the second switch for operation thereof at preselected intervals; and a second movable actuator selectively engaging said means for controlling the second switch; and means operatively connected with the control member for disengaging said second actuator from said means for operating the second switch as the result of a movement of the control member away from said first position.

12. in a control such as for controlling a refrigeration apparatus, mechanism comprising: a control member; a first switch; a second switch; means for translating the control member selectively to first and second positions as a function of a temperature of the refrigeration apparatus; a first actuator pivotable about a first axis for controlling the first switch; means on the control member selectively engaging the first actuator to pivot the same about said first axis as the result of the movement of the control member toward said second position; means controlling the second switch for operation thereof at preselected intervals; and a second actuator pivotable about a second axis and selectively engaging said means for controlling the second switch; and meansoperatively connected with the control member for disengaging said second actuator from said means for controlling the second switch as the result of a movement of the control member toward said first position.

13. The mechanism of claim 12 wherein the means on 1 1 the control member engaging the first actuator comprises means defining an abutment facing in the direction from said first position to said second position.

14. The mechanism of claim 12 wherein the translating means comprises a spring biased diaphragm and means defining a pressure chamber confronting the diaphragm opposite said control member for development of fluid pressures therein corresponding to a temperature of the refrigeration apparatus.

15. In a control such as for controlling a refrigeration apparatus, mechanism comprising: a control rod; a switch; means for axially translating the control rod selectively to first and second positions as a function of a temperature of the refrigeration apparatus; means defining a pivot; an actuator for controlling said switch, said actuator being pivotable about said pivot; means on the control member selectively engaging said actuator LO move the same about said pivot as the result of the movement of the control member toward said second position; and means for adjusting said pivot to adjust the position of engagement of said actuator by said means on the control member.

16. The mechanism of claim 15 wherein the means for adjusting the pivot comprises a cam, a handle connected to the cam for manual rotation thereof, and a finger on the pivot engaging the cam for adjustably positioning the pivot.

17. The mechanism of claim 15 wherein the actuator includes a pair of oppositely projecting ears and the adjusting means includes means defining a pair of trapezoidal slots pivotally receiving the ears, said adjusting means being pivotally mounted for movement of the slots to any 12 one of a number of positions spaced in the direction of movement of the control rod.

18. In a control such as for controlling refrigeration apparatus, mechanism comprising: a control rod having an axial recess in one end; a first switch; a second switch; means for axially translating the control rod selectively to first and second positions as a function of the temperature of the refrigeration apparatus; a first actuator pivotable about a first axis for controlling the first switch; means on the control rod selectively engaging the first actuator to pivot the same about said first axis as a result of the movement of the control rod toward said second position; means controlling the second switch for operation thereof at preselected intervals; a second actuator pivotable about a second axis and selectively engaging said means for controlling said second switch, said second actuator including a connector having a ball portion received in said control rod recess for pivoting the second actuator as a result of axial movement of the control rod in the direction of opening of the recess; and means operatively connected with the control rod for disengaging said second actuator from said means for controlling the second switch as a result of the movement of the control rod toward said first position.

References Cited in the file of this patent UNITED STATES PATENTS 

15. IN A CONTROL SUCH AS FOR CONTROLLING A REFRIGERATION APPARATUS, MECHANISM COMPRISING: A CONTROL ROD; A SWITCH; MEANS FOR AXIALLY TRANSLATING THE CONTROL ROD SELECTIVELY TO FIRST AND SECOND POSITIONS AS A FUNCTION OF A TEMPERATURE OF THE REFRIGERATION APPARATUS; MEANS DEFINING A PIVOT; AN ACTUATOR FOR CONTROLLING SAID SWITCH, SAID ACTUATOR BEING PIVOTABLE ABOUT SAID PIVOT; MEANS ON THE CONTROL MEMBER SELECTIVELY ENGAGING SAID ACTUATOR TO MOVE THE SAME ABOUT SAID PIVOT AS THE RESULT OF THE MOVEMENT OF THE CONTROL MEMBER TOWARD SAID SECOND POSITION; AND MEANS FOR ADJUSTING SAID PIVOT TO ADJUST THE POSITION OF ENGAGEMENT OF SAID ACTUATOR BY SAID MEANS ON THE CONTROL MEMBER. 